|PIVIK, R - Arkansas Children'S Nutrition Research Center (ACNC)|
|ANDRES, ALINE - Arkansas Children'S Nutrition Research Center (ACNC)|
|TENNAL, KEVIN - Arkansas Children'S Nutrition Research Center (ACNC)|
|GU, YUYUAN - Arkansas Children'S Nutrition Research Center (ACNC)|
|CLEVES, MARIO - Arkansas Children'S Nutrition Research Center (ACNC)|
|Badger, Thomas - Arkansas Children'S Nutrition Research Center (ACNC)|
Submitted to: International Journal of Psychophysiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2015
Publication Date: 5/1/2015
Citation: Pivik, R.T., Andres, A., Tennal, K.B., Gu, Y., Cleves, M.A., Badger, T.M. 2015. Infant diet, gender and the development of vagal tone stability during the first two years of life. International Journal of Psychophysiology. 96(2):104-114.
Interpretive Summary: Do differences in early infant diet affect the development of individual differences in brain-behavior functions? A fundamental property of individual difference measures is their stability over time. We studied the stability of a physiologic measure of heart rate control--vagal tone--which was determined at 3, 6, 9, 12, and 24 mo from resting heart rate recordings in healthy breastfed (BF), milk formula-fed (MF), or soy formula-fed (SF) infants. The stability of resting vagal tone has been related to behavioral measures of temperament in infants and children. We found that vagal tone stability was better maintained in breast-fed than formula-fed groups across 3 month intervals during infancy, and that stability between infancy and 2 years emerged earlier in BF and MF than SF infants and later in boys than girls. Furthermore, we identified a period during infancy (6-9 mo) when for all groups stability was greater than at any other time--suggesting this may be an important transitional period in factors influencing vagal regulation. These findings provide a better understanding of the development of vagal tone stability and suggest that infant diet may help determine individual differences in functions underlying social-emotional interactions known to be influenced by heart rate regulation.
Technical Abstract: Postnatal nutrition influences neurodevelopment, including autonomic nervous system components associated with cardiac control. In this study resting vagal tone (V) was measured quarterly during infancy and at 2 years in 146 breast-fed, 143 milk formula-fed, and 137 soy formula-fed infants. Stability of V across infancy was consistently significant for BF than formula-fed infants. Stability was similar for boys and girls in BF and SF groups but was higher in boys than girls in the MF group. Significant stability between infancy and 2 years emerged later in SF than other groups and later in boys than girls. For all groups stability peaked between 6 and 9 months – a time when postnatal vagal myelination slows and which may represent a pivotal stage in the development of V stability. These findings indicate that infant diet and gender are important modulators of early development of autonomic state control.